Tube pointer



D. W. ROW'ELL TUBE POINTER Dec. 18, 1962 2 Sheets-Sheet 1 Filed April22, 1960 FIG. 2

a m F INVENTOR. DOUGLAS W- ROWELL ATTORNEYS Dec. 18, 1962 D. w. ROWELLTUBE POINTER 2 Sheets-Sheet 2 Filed April 22, 1960 FIG. 6

INVENTOR DOUGLAS W. ROWELL.

BY fzwwug W ak Q ATTORNEYS 3,058,929 Patented Dec. 18, 1962 nice3,068,929 TUBE POINTER Douglas W. Rowell, North Woodbury, Conn.,assignor to Anaconda American Brass Company, a corporation ofConnecticut Filed Apr. 22, 1960, Ser. No. 23,953 9 Claims. (Cl. 153-34)This invention relates to the pointing of tubes and, more particularly,to a new method and apparatus for pointing tubes wherein cooperatingmovable and stationary dies deform and compact an end portion of thetube in two strokes into a polygonal cross section substantially smallerthan the across section of the tube.

Before a tube'is drawn, it is necessary to point or reduce the diameterof the end portion of the tube so that it can be inserted through thedie and be grasped by tongs or other gripping device of the drawingapparatus, Though such reduction in diameter has often been accomplishedby necking down the end portion of the tube in a swaging operation, ithas been found to be quicker and easier to collapse the tube end portionwithout upsetting the wall or substantially displacing the metal as inswaging. However, presently available methods of collapsing the endportion of tubes entail considerable die wear and produce collapsedportions which are either lacking in symmetry or are too large to berepeatedly insorted through a considerable number of successivelysmaller dies. Asymmetry in a tube point gives rise to stressconcentrations which often cause breakage of the pointed portion of thetube during'drawing. Short die life and the relatively large size of thetube points are disadvantages which increase operating costs and scraplosses.

' The major purpose of the present invention is to provide a new methodand apparatus for pointing tubes by the wall-collapsing method whichovercomes these various shortcomings in the means presently available,According to the invention, a pointed end portion of polygonal crosssection is formed on the tube by two rapid immediately successivestrokes of cooperating movable and stationary dies. (The term polygonalis used here and throughout the specification and claims in its acceptedmeaning of more than four sides.) The walls of the tube'are compressedsolidly into this polygonal shape without causing substantial flow ofmetal and thus the work required to accomplish the operation is minimal.it has been found in practice that the resulting point can be madesufficiently small in size relative to the original tube diameter topermit the tube to be inserted into and drawn through a considerableseries of successively smaller dies before it need be repointed. At thesame time, the polygonal shapes themselves possess good symmetry, andcan readily be formed symmetrically with respect to the cylindricaltube, so as to minimize the risk of concentrations of stress during thedrawing operation which might cause fracture of the point. The point isformed without reducing the thickness of the tube walls, so the pointremains as strong for pulling through the dies as the main body of thetube. Furthermore, the polygonal point is formed in a fashion whichincreases die life by substantially reducing the wear to which theforming dies are subjected.

The tube pointing apparatus of the invention comprises a frame and astationary die afiixed to the frame. First and second movable dies aredisplaceable between open and closed positions relative to thestationary die. Means are included for forcibly displacing the movabledies between their open and closed positions. The dies togetherpartially define an opening sufficiently large to receive the tube to bepointed when the movable dies are in their open position. When themovable dies are in closed position, the dies together define a cavityof polygonal cross section which is substantially less in maximum width(corner to corner) than the outside diameter of the tube. In thiscavity, the stationary die defines at least two adjoining sides of thepolygon and the first and second movable dies define the remaining sidesthereof.

In a preferred form of the apparatus, the cavity is of hexagonal crosssection. The stationary die then defines three adjoining sides of thehexagonal cavity, the first movable die defines one side, and the secondmovable die defines the remaining two adjoining sides.

The tube may first be deformed by one movable die and then by the otherin two immediately successive strokes. Preferably, the first movable diein actuated be? fore the second movable die to partially flatten thetube. The tube is thus prepared for actuation of the second movable diewhereby the partially flattened configuration is collapsed into analmost solid polygonal point. There is very little sliding contactbetween the tube and the dies in forming the point in this manner andhence die wear is minimized. Also, a great amount of compression of thecollapsed wall is made possible so that the poly: gonal point isexceptionally compact, without reducing the thickness of the tube walls.

The invention also provides a new method which is carried out by meansof the apparatus. In general, the method comprises the steps ofpartially flattening the portion of the tube to be pointed intosubstantially oblong cross sectional shape having rounded ends. Therounded ends are then compressed toward one another while the remainderof the portion is constrained from outward dis: placement. Hence, thegreater part of the portion of the tube being pointed is collapsedinwardly. The compression is ceased when the end portion of the tubej'issubstantially fully compacted into a polygonal cross section.

A preferred embodiment of the new apparatus illustrating the steps ofthe method is shown in the accompanying drawings, wherein FIG. 1 is aschematic fragmentary elevation of the apparatus partly in sectionshowing the movable dies in open position with a tube to be pointed intohexagonal cros section received between the dies;

FIG. 2 is a similar view showing the first movable die after it hasreached its closed position and the second movable die still in its openposition;

FIG. 3 is a similar view showing both movable dies in their closedposition and the tube pointedin hexagonal shape;

FIG. 4 is a fragmentary perspective view partly broken away showing theresulting hexagonal end portion of the tube;

FIG. 5 is a view similar to FIG. 1 showing dies for forming an octagonalpoint on the tube;

FIG. 6 is a view similar to FIG. 2 of the apparatus of FIG. 5;

FIG. 7 is a view similar to FIG. 3 showing the dies fully closed and thetube pointed in octagonal shape; and

FIG. 8 is a fragmentary perspective view partly broken away showing theresulting octagonal end portion of the tube.

Referring first to the embodiment of FIGS. 1-4, a stationary frame lit)is provided to define adjoining vertical 5 and horizontal die supportingsurfaces 11 and 12 respecforcibly displaced toward the respectivevertical and horizontal surfaces of the frame.

Affixed to the frame i a stationary die which (in the form shown) ismade up of two blocks 16 and 17. One die block 16 rests on thehorizontal surface 12 and abuts the vertical surface 11 of the frame,and the other die block 17 also rests on the horizontal surface 12 ofthe frame and adjoins the lower portion of the first die block 16. Thedie blocks 16 and 17 are disposed in opposition to the horizontalplunger 14 and vertical plunger 13 respectively. Each die block has alength perpendicular to the axes of both plungers which is at leastequal to the length of the pointed portion to be formed on the tube.

Formed in the vertical surface of the first die block 16 which faces thehorizontal plunger 14 is a concave V-shaped groove 19 extendingperpendicular to both plunger axes throughout the length of the dieblock 16. The groove is defined by two fiat surfaces of equal dimensionwhich converge at an included angle of substantially 120. Adjoining andextending upwardly from the top edge of the groove 19 is a verticalsliding surface on the die block 16. The upper surface 22 of the seconddie block 17 adjoins the lower edge of the groove 19 and is flat andhorizontal. Thus, it is perpendicular to the first sliding surface 20 onthe die block 16, and forms an included angle of substantially 120 withthe lower of the two fiat surfaces defining the groove 19.

Aifixed to the face of the vertically movable plunger 13 is a firstmovable die 23. The movable die 23 is formed with a working face whichis fiat and horizontal and which is therefore parallel and opposed tothe surface 22 of the lower stationary die block 17. This first movabledie 23 extends into contact with and slides against the first slidingsurface 20 on the die block 16. In the retracted position of the plunger13 shown in FIG. 1, the distance between the working face 25 of thefirst movable die 23 and the surface 22 of the die block 17 is greaterthan the outside diameter of the tube to be pointed.

A second movable die 27 is affixed to the face of the horizontallymovable plunger 14. This die 27 includes a base portion 28 and aprojecting portion 29 which extends therefrom between the first movabledie 23 and the die block 17. Formed in the outer face of the projectingportion 29 of the second movable die 27 is a V-shaped groove 30 definedby two fiat surfaces of equal dimension which converge at an angle ofsubstantially 120. The dimensions of the groove 30 are equal to those ofthe groove 19, which is directly opposite thereto. The verticaldimension of the projecting portion 29 is equal to the edge-to-edgedimension of the groove 30 formed in its outer face; and this projectingportion 29 is adapted to slide along the surface 22 of the die block 17.The outermost end of the projecting portion 29 extends from the shoulderof the base portion 28 a distance such that in the forward position ofthe plunger 14 the projecting portion 29 stops short of the nearestpoint on the die block 16 a distance equal to the Width of the fiatsurfaces defining the grooves 19 and 30. In that forward position of theplunger 14, the shoulder of the base portion 28 abuts the sides of thefirst movable die 23 and the stationary die block 17, which serve asstops to limit the forward motion of the horizontally movable die 27.

Each of the movable dies 23 and 27 has a dimension perpendicular to theaxes of both plungers which is equal to that of the stationary dies. Intheir open position shown in FIG. 1, the movable dies partly define anopening sufficiently large to receive the tube to be pointed.

In the operation of the new tube-pointing apparatus, the end portion ofa tube 32 is inserted between the dies when the plungers 13 and 14 arein their open position.

The tube 32 should be small enough to fit between the 4 wardly to itsclosed position shown in FIG. 2. In this closed position, the workingface 25 of the first movable die 23 stops at the upper edge of thegroove 19 formed in the die block 16. As shown in FIG. 2, this causesthe tube 32 to be flattened into oblong cross sectional shape havingsubstantially parallel sides and rounded ends. It will be noted that theworking face 25 of the first movable die 23 also abuts against the endof the projecting portion 29 of the second movable die 27 when thisinitial stroke is completed.

Next, the plunger 14 is moved forwardly into its closed position shownin FIG. 3. This causes the projecting portion 29 of the second movabledie 27 to slide between the first movable die 23 and the lowerstationary die block 17 into a position where the dies together define acavity of regular hexagonal shape. The groove 19 in the stationary dieblock 16 defines two sides of this hexagonal cavity and a portion of thesurface 22 of the stationary die block 17 defines a third side adjoiningthereto. Opposite the die block 17, a portion of the working face 25 ofthe first movable die 23 defines one other side of the hexagonal cavity,and the remaining two adjoining sides are defined by the groove 30 inthe projecting portion 29 of the second movable die 27.

While moving into its closed position shown in FIG. 3, the secondmovable die 27 first compresses the rounded ends of the tube 32 towardone another between the wedge-shaped grooves 19 and 30. At the sametime, the parallel sides of the tube 32 are constrained between thefirst movable die 23 and the die block 17. This causes the parallelsides of the oblong cross section to collapse inwardly as shown in FIG.4, and the previously rounded ends thereof are formed into a triangularshape conforming to the shape of the grooves 19 and 30. Compression ofthe tube in this manner ceases when the shoulder of the base portion 28of the second movable die member 27 abuts the first movable die member23 and the lower die block 17; and at that point the cavity formed bythe dies is of the desired regular hexagonal shape.

The collapsed portion of the tube between the dies is formed into theshape shown in FIG. 4 with a definite hexagonal cross section. Twoopposite sides 35 and 36 of this cross section are marked by folds wherethe walls of the tube were collapsed inwardly, but the remaining foursides are substantially fiat. It will be noted that the collapsed wallsof the tube 32 are substantially unchanged in thickness, but arecompressed together to such a degree that the point is almost solid. Themaximum width of the hexagonal cross section of the pointed portion 33(measured from corner to corner) is considerably less than the originaloutside diameter of the tube 32. The length of the pointed portion 33can be varied, of course, as desired, by correspondingly varying thelength (in the direction perpendicular to the plane of the drawing) ofthe dies in the apparatus.

Turning now to the embodiment of the new apparatus shown in FIGS. 5-8, aframe 35 is associated with vertical and horizontal plungers 36 and 37as in the embodiment described above. Mounted on the frame 35 is astationary die made up of two blocks 39 and 40 which are supported inthe same manner as the die blocks 16 and 17. The first die block 39 hasa concave V-shaped groove 41 formed in its vertical surface opposite thehorizontal plunger 37. This groove defines an included angle of Thesecond block 40 also includes a 135 V- shaped groove 42 opposite thevertical plunger 36 and the immediately adjoining surfaces of these twogrooves also define an included angle of 135.

First and second movable dies 44 and 45 are mounted on the vertical andhorizontal plungers 36 and 37 respectively to slide against the dieblocks 39 and 40 as in the previous embodiment. However, a V-shapedgroove 46 is formed in the first movable die 44 and defines an includedangle of 135. Similarly, the second movable die 45 defines a 135V-shaped groove 48. Hence, when the dies 44 and 45 are brought togetherthey define a regular octagonal cavity with the stationary die blocks 39and 48.

The end portion of a tube 50 which is to be pointed is first insertedbetween the stationary and movable dies as shown in FIG. 5. The verticalplunger 36 is then actuated to bring the first movable die 44 down ontothe end of the tube 50 to liatten it into the substantially elongatedshape shown in FIG. 6. The ends of this oblong cross section arerounded.Next, the horizontal plunger 3'7 is actuated to bring the second movabledie 45 against the flattened end portion of the tube so that the tube iscollapsed as shown in FIG. 7. Upon retraction of the dies, the tube iswithdrawn and formed with a pointed portion 52 as shown in FIG. 8. Theportion 52 is of substantially regular octagonal shape with the greaterpart of the tube walls collapsed inwardly in a substantially solidfashion.

It is evident that the regular polygonal portions of the tubes pointedby these embodiments of the new apparatus are of symmetrical shape andthus are not susceptible to extreme stress concentrations when graspedby tongs during drawing. Also, the polygonal pointed portions are ofsmall size compared to the original tube and thus can be received in awide size range of grips. Such fiat-sided configurations on the tubepoints need not be specially matched to the gripping jaws as is the casewith conventional round points. By collapsing a tube into the polygonalshapes shown, very little wear is exerted on the dies of the apparatusbecause there is a minimum of sliding contact between the walls of thetubes and the dies. Furthermore, there is virtually no reduction inthickness of the metal in deforming the walls of the tubes in the mannerdescribed, so that the new pointing operation can be performed quicklywith a minimum of work and without reducing the tensile strength of thetube at its point in comparison with the cylindrical body of the tube.

I claim:

1. Tube pointing apparatus comprising a frame, a stationary die affixedto said frame, first and second movable dies displaceable at rightangles to one another between open and closed positions relative to saidstationary die, means for forcibly displacing said movable dies betweentheir open and closed positions, said dies together partially definingan opening sufiiciently large to receive the tube to be pointed whensaid movable dies are in open position, said dies together defining acavity of polygonal cross section substantially less in maximum widththan the maximum width of said tube when said movable dies are in closedposition, said first and second movable dies defining at least threeadjoining sides of said cavity.

2. Tube pointing apparatus according to claim 1 wherein said cavity isof hexagonal cross section, said stationary die defining three adjoiningsides of said cavity, said first movable die defining one side of saidcavity, and said second movable die defining two adjoining sides of saidcavity.

3. Tube pointing apparatus according to claim 1 wherein said cavity isof octagonal cross section, said stationary die defining four adjoiningsides of said cavity, said first movable die defining two adjoiningsides of said cavity, and said second movable die defining two adjoiningsides of said cavity.

4. Tube pointing apparatus comprising a frame, a stationary die affixedto said frame, first and second movable dies displaceable at rightangles to one another between open and closed positions relative to saidstationary die, said stationary die defining a first surface againstwhich said first movable die is adapted to slide between its open andclosed positions, said stationary and first movable dies definingparallel second surfaces perpendicular to said first surface againstwhich said second movable die is adapted to slide from its open to itsclosed position, means for forcibly displacing said movable dies betweentheir open and closed positions, said dies together partially definingan opening suificiently large to receive the tube to be pointed whensaid movable dies are in open position, said dies together defining acavity of regular polygonal cross section substantially less in maximumwidth than the maximum width of said tube when said movable dies are intheir closed position, said stationary die defining at least twoadjoining sides of said cavity, said first movable die defining at leastone side of said cavity, and said second movable die defining at leasttwo adjoining sides of said polygonal cavity.

5. Tube pointing apparatus comprising a frame, a stationary die afi'ixedto said frame, first and second movable dies displaceable at rightangles to one another between open and closed positions relative to saidstationary die, said stationary die defining a first surface againstwhich said first movable die is adapted to slide between its open andclosed positions, said stationary and first movable dies definingparallel second surfaces perpendicular to said first surface againstwhich said second movable die is adapted to slide from its open to itsclosed position, means for forcibly displacing said movable dies betweentheir open and closed positions, said dies together partially definingan opening sufliciently large to receive the tube to be pointed whensaid movable dies are in open position, said dies together defining acavity of regular hexagonal cross section substantially less in maximumwidth than the maximum width of said tube when said movable dies are intheir closed position, said stationary die defining three adjoiningsides of said cavity, said first movable die defining one side of saidcavity, and said second movable die defining two adjoining sides of saidhexagonal cavity.

6. Tube pointing apparatus according to claim 5 wherein said parallelsecond surfaces on said stationary and first movable dies respectivelyare coplanar with and adjoin diametrically opposite parallel sides ofthe regular hexagonal cavity defined by said dies when the movable diesare in closed position.

7. Tube pointing apparatus comprising a frame, a stationary die affixedto said frame, first and second movable dies displaceable at rightangles to one another between open and closed positions relative to saidstationary die, said stationary die defining a first surface againstwhich said first movable die is adapted to slide between its open andclosed positions, said stationary and first movable dies definingparallel second surfaces perpendicular to said first surface againstwhich said second movable die is adapted to slide from its open to itsclosed position, means for forcibly displacing said movable dies betweentheir open and closed positions, said dies together partially definingan opening sufficiently large to receive the tube to be pointed whensaid movable dies are in open position, said dies together defining acavity of regular octagonal cross section substantially less in maximumwidth than the maximum width of said tube when said movable dies are intheir closed position, said stationary die defining four adjoining sidesof said cavity, said first movable die defining two adjoining sides ofsaid cavity, and said second movable die defining two adjoining sides ofsaid octagonal cavity.

8. A method of pointing tubes which comprises initially partiallyflattening the portion of the tube to be pointed with a singleflattening stroke into substantially oblong cross sectional shape havingrounded ends, compressing at least part of said rounded ends toward oneanother with a single compression stroke along a single side section ofthe tube while constraining the remainder of said portion of the tubefrom outward displacement, thereby collapsing inwardly the greater partof said portion of the tube, and ceasing said compression when saidportion of the tube is substantially fully compacted into a polygonalcross section.

I 9. A method of pointing tubes which comprises initially partiallyflattening the portion of the tube to be pointed with a singleflattening stroke into oblong cross sectional shape having substantiallyparallel sides and rounded ends,

7 compressing said rounded ends toward one another between concavelywedge-shaped dies with a single compression stroke along a single sidesection of the tube while constraining said parallel sides from outwarddisplacement thereby forming each of the rounded ends of said 5 oblongcross section into triangular shape and collapsing inwardly a portion ofthe parallel sides of said oblong cross section, and ceasing saidcompression when said portion of the tube is substantially fullycompacted into a regular hexagonal cross section.

References Cited in the file of this patent UNITED STATES PATENTSWikstrom Jan. 16,

Oliver et a1. June 16,

Frank et a1. Jan. 3,

Rotheroe Mar. 11,

FOREIGN PATENTS Germany May 21,

Great Britain Mar. 11,

